English players are at loggerheads with Premiership Rugby's proposals for an 11-month domestic season to run after the 2019 World Cup, with murmurings of strike continuing over welfare and rest periods.

But the RFU is attempting to determine the ideal off-season rest time, with Nigel Melville insisting that could hold the key to solving the disputes.

"The important factor will be data and information in determining how long the off-season should be," said Melville, the RFU's professional rugby director.

"I think that actually will determine how long the season will be.

"We have the EPS (Elite Player Squad) deal with the players, so we know the elite players, what they are going to get, their 10 weeks et cetera.

"But what about the rest of the game? What is the ideal off-season?

"So we are doing some sports science work on that to work out what that should be.

"There's no point sitting in a room and talking about what the off-season should be until we've got the data and the science to say 'it should be this'.

"And the players will be at the heart of that, what is the best off-season for a player.

"Once we get that I think we can work out where the start should be, and working with Premiership Rugby to see where their fixtures will go."

The RFU insists its plan to become England's strongest sport does not mean any bid to overtake football as the nation's premier game.

But their latest four-year plan involves renewed commitments to governance and success, with their tilt to win World Cup 2019 remaining central.

The RFU revealed a planned initiative called X Rugby, a hybrid version of 15-a-side and Sevens, designed to attract new youngsters to the sport.

The X Rugby format is likely to be rolled out within the next 12 months, as the RFU examine ways to boost numbers at grassroots level.

At the game's pinnacle however, exorcising the spectre of a players' strike remains paramount.

"There's lots still to be worked out; we're closer than we have been for a long time, but now we're going to the next stage," said Melville.

"It's about ourselves, PRL and the RPA (Rugby Players' Association) sitting down, and ultimately all that will go through the PGB (Professional Game Board).

"We know where we are with the EPS players on a 10-week break, we know the RPA have put out a 14-week figure.

"But where the sports scientists fit on that range it will be interesting to see.

"Let's work out the best thing, let's work that out, because actually that determines when you start and when you finish."